Sweeping device for boiler tubes



Aug. 18, 1925. 1,549,841

F. LJUNGSTROM SWEEPING DEVICE FOR BOILER TUBES Filed NOV. 26, 1920 Invent f? Lju 55 5 Patented Aug. 18, 1925.

U N l f. S T E S PATENT OFFICE.

FREDBIK LJUNGSTRSM, F BREITIK, SWEDEN, ASSIGNOR T0 AKTIEBOLAGET LJUNGSTRGMS ANGT'UZRBIN, O'F STOQKHOLM, SWED N, A CORPORATION.

SWEEPI'NG DEVICE FOR BOILER TUBES.

Application filed November 26, 1920. Serial No. 426,570.

To all whom it may concern:

Be it known that I, FREDRIK LJUNG- sTuoM, chief engineer, a subject of the King of Sweden, residing at Brevik, Lidingon,

Sweden, have invented certain new and use ful Improvements in Sweeping Devices for Boiler Tubes, of which the following is a specification.

Experience has proved that in steam boilers provided with tubes deposit of soot on the tubes or the like exerts a great influence on the efficiency of the boiler. This is particularly the case in inultitubular boilers having superheater tubes entering the lire tubes. To prevent said inconvenience apparatus have been constructed generally working by means of steam jets adapted to effect the sweeping operation while using the boiler. Such apparatus have generally been located in the smoke box, and the injection of the steam has been effected in the direction towards the flow of the flue gases. In such constructions, howover, all the tubes cannot be cleansed simultaneously but only in small groups. On account thereof it has been difficult to construct an apparatus which may be easily operated from the outside of the smoke box. Said difficulties have particularly been met so with in locomotives which when running should be capable of being swept from the drivers cabin.

Besides it has been difficult to construct a soot blower located close enough to the openings of the boiler tubes thus bringing about the most strenuous effect without interfering with the superheating device when being mounted or impeding the inspection of the same. Obviously said both, apparatus should be removable entirely or in part independent of each other.

This invention relates to a steam soot blower by means of which said difficulties are prevented. The apparatus is in wellknown manner located in the smoke box and effects the sweeping by the aid of steam jets directed towards the flue gases. The invention is characterized by its pipe system being stationary and so arranged that the sweeping is performed on groups each comprising one or more boiler tubes.

Further the invention consists in that, in case the flue gases are also used for preheating the air passing to the furnace, the

- soot blower is us d. in t e same .01 i a m d fied form for sweeping also said air preheating apparatus.

In the accompanying drawing Fig. 1 il lustrates a constructional form of a soot blower constructed according to the invention and so arranged that the apparatus performs also the sweeping of the air preheater. This form of the sweeping apparatus is very suitable in steam boilers provided with superheatin'g tubes, because of being independent of such tubes. Fig. 2 shows a portion of the device viewed from the side and Fig. 3 a detail to a larger scale.

Referring to the drawing, 1 designates the tube plate of the boiler to which the tubes 2 are secured in vertical rows. Located in the smoke box 3 (Fig. 2) is the soot blower consisting of a number of vertical pipes t mounted on nozzles 7 projecting from a common steam supply pipe 5. Said pipes 4 are provided with apertures or nozzles 6 directed towards the openings of the boiler tubes and are placed in every other interspace between the rows of boiler tubes.

By placing the vertical tubes of the soot blower in this manner, several advantages are attained, particularly that the diflerent tubes may be exchanged independent of each other, while besides a less number of vertical pipes is necessary.

Since all the boiler tubes are not to be cleansed at the same time, steam should not be supplied to all the vertical pipes simultaneously but only to one pipe or to a few pipes at the same time. This controlling of the flow of steam should preferably be effected automatically in such manner that all the tubes of a group can be cleansed simply by turning a hand wheel or the like, then all the tubes of another group and so on.

In the embodiment shown this automatic distribution of steam is effected by means of the. common steam tube 5 extending along the tube plate. To this purpose the said tube is provided inside with a rotary tubular distributing valve. The vertical pipes l mounted on the common steam tube 5 are by means of the nozzles 7 placed on the steam tube 5 connected with the interior of the said steam tube. The nozzles are through apertures 9 in the wall of the tube 5 connected with the interior of this tube. The apertures 9 are located in a straight line. The inner tubular valve is on the contrary provided with apertures 9 placed in different angular positions thus supplying, when be ing turned, the steam passing through the same to the vertical pipe whose opening 9 in the tube 5 communicates with the corresponding aperture 9. When turning the valve one revolution, the different pipes iwill be successively connected with the interior of the steam tube 5 or rather with the interior of the distributing valve. This valve is in the embodiment shown divided in several parts in such manner that each part forms a small pipe or sleeve 8 corresponding to one or more apertures 9. Said pipes or sleeves 8 engage one another in such manner that, when turning one of th m, for instance that one adjacent to the turning device 10, the other e. will be carried along. The steam admitted to the soot blower through the inlet 11 and for instance supplied from the boiler or the superheater enters first the interior of the valve and is then distributed to the different vertical pipes in proper course.

Owing to the limited space available for the sweeping device, particularly in case of a superheater being used, diiiiculties are met with inconstructing the apparatus-in such mamier that the different vertical pipes are removable independently of one another for inspection or the like. This difiiculty has been overcome in the embodiment shown by so mounting the vertical pipes at the common steam tube that they telescopically receive the respective nozzles, tightening being obtained by clamping the vertical pipes against the said nozzles. This clamping is effected by the aid of a supporting point 13 close to the steam pipe 5 for the upper portion ofthe pipes a and a tightening bolt 14 in the lower portion of the smoke box for each of said pipes 4t. Each vertical pipe is mounted in this manner by first inserting the pipe in a position corresponding to the line 16 in such manner that the connecting cone 26 (Fig. 3) bears against the stationary pin 27, the lower portion-of the/pipe then being lowered in the direction of the arrow 15 and tightened by means of the bolt 14'. Onaccount of the cylindrical or spherical surfaces at the opening of the pipe 4 and the nozzle 7 the tube will center itself, the proper tightening being eiiectod at the same time. An

.absolute tighteningis not necessary, when the soot blower is acted upon by the steam only when cleansing is to be effected, in which case a slight leakage is of no importance. The supporting point. should preferably be adjust-a is, for instance by the cone-26 being adapted to be screwed up and down inthe sleeve 28.

In steam plants in which the waste gases are used for heating the air passing to the furnace, which especially may be the case in locomotives, the present soot-blower may in suitable-combination be usedfor sweeping said air preheating device. This air preheating device is preferably located beneath the locomotive at the front thereof and soar-ranged that the waste gases pass about a pipe system through which the air to be heated is conducted. Such an embodiment is shown in the drawing, the vertical pipes i passing in front of the tube plate of the boiler being connected by means of pipes 12 with pipes 17 extending between the pipes 19 of the air preheater 18. Should the air preheater comprise more pipes than the number of tubes in the corresponding boiler or in case it should otherwise be deemed appropriate, a number of pipes 17 are made to correspond to each pipe 4 and to be connected with corresponding pipes 12 by means of a distributing pipe 29; The pipes 17 like the pipes t are provided with apertures 20 so directed that the steam in a suitable manner blows away soot and dross between the pipes. This cleansing will obviously also take place in groups, since said pipes 17 are supplied with steam from the corresponding pipes el and in the same course as the latter.. The removed dross etc. is collected in a separate dross collector 21 which may be emptied from time to time. This dross collector should preferably be so located that the dross is blown into the same by the steam jets, and it should therefore, as far as space allows, extend along the whole width of the air preheater; besides the collector should be located at the end of the air preheater opposite-to the cleansing pipes 17 of the sweeping device.

Should not the space allow-the dross collector to extend along the whole width of the air preheater, one or more of thepipes 19 may suitably be replaced by steam pipes connected With corresponding pipes 17 and be provided with apertures so directed that the dress or sootaccumulated at the sides is blown downinto the dross collector.

The drawing shows how a pipe 23 in this manner is adapted to blow-ofi' pipe. Said pipe 23 connected with the corresponding pipe 17 is provided with apertures 25 through which steam is blown, the pipe being preferably placed a little lower than the other pipes1'9, and owing thereto-the dross collected on the-bottom of the preheater 18- is blown down into the dross col lector 21.

lVhat-I claim as new and desire tosecure by Letters Patent of the United States is 1. In. a boiler structure, the combination with boiler tubes disposed in spaced vertical rows, of a steam distributing device, stationary vertical steam distributing pipes arranged in front of the interspaces between said vertical rows of boiler tubes and pro 'vided with outlet means positioned to clean the respective tubes, and connections between said distributing device and said distributing pipes and valve means so arranged as to supply steam successively to said distributing pipes from said device.

2. In a boiler structure, the combination with boiler tubes disposed in vertical rows, of a steam distributing device, stationary vertical steam distributing pipes arranged in front of every second interspace between said vertical rows of boiler tubes and provided with outlet means positioned to clean the respective tubes, connections between said distributing device and said distributing pipes and valve means so arranged as to supply steam successively to said distributing pipes from said device.

3. In a boiler structure, the combination with boiler tubes disposed in vertical rows, of a steam distributing device, stationary vertical steam distributing pipes arranged in front of the interspaces between said vertical rows of boiler tubes and provided with steam exhaust openings adapted to ef fect cleaning of the boiler tubes, connections between said distributing device and said distributing pipes, and valve means so arranged as to supply steam successively to said distributing pipes.

45. In a'boiler structure, the combination with boiler tubes disposed in vertical rows, of a steam distributing device, stationary vertical steam distributing pipes arranged in front of every second interspace between said vertical rows of boiler tubes and provided with steam exhaust openings positioned to effect cleaning of the boiler tubes of the two rows lying on opposite sides of said distributing pipes, connections includ ing nozzles between said distributing device and said distributing pipes, and valve means arranged so as to control the supply of steam successively through said distributing pipes.

In testimony whereof I afiix my signature.

FREDRIK V LJUNcsTRoM. 

